1. Field of the Invention
The present invention pertains to surgery, and more particularly, pertains to tissue and/or corneal preservation systems for storing corneas or other organs for subsequent transplant.
2. Description of the Prior Art
The prior art systems maintain living cornea tissue in a suspension of death, through freezing or refrigeration. These systems have been less than desirable in that the tissue progressivly looses viability during storage, the tissue has been of questionable sterility, and it has not been adaptable to store the tissue at various and fluctuating temperatures.
Numerous articles have been published regarding organ preservation for transplantations such as that by Karow and Pegg, Organ Preservation for Transplantation, 1981. Pages 428-441 were specifically devoted to the "cornea".
Another prior art article devoted to the subject is "Organ Cultural Corneal Storage at Ambient Room Temperature" by Richard L. Lindstrom, M.D., from the Archives of Ophthalmology, May 1077, Volume 95, page 869-878, which delineate the prior art.
The endothelial cell is of primary importance in the maintenance of normal corneal transparency. Since adult human corneal endothelial cells have limited, if any, regenerative capacity, the success of penetrating kertoplasty (corneal transplantation) in humans depends on transplanting an adequate amount of functioning donor endothelium.
Therefore, any method used to store the donor cornea, from the death of the donor to its transplant into the recipient, must maintain endothelial cell viability.
Present methods include refrigeration of the whole globe at 4.degree. centigrade, which results in a progressive loss of endothelial cells at this low temperature. Although the use of TC199 with Dextran (M-K media) at 4.degree. centigrade to store the cornea-scleral segment, may increase the duration of storage to 96 hours, prolonged preservation is again not possible because of progressive endothelial cell death. Cryo preservation allows a storage time of up to at least one year but the complex technology limits its use to a few centers. In addition, a high rate of endothelial cell death in common following tissue thawing.
The present invention overcomes the disadvantages of prior art by providing a universal corneal preservation system, which as a closed system provides for sterility and intermediate to long-term corneal storage. The flexibility and simplicity of the system may be particularly useful in third-world countries.